diff --git a/jconfig.h.in b/jconfig.h.in
index 1ae74ddc..93de0a6d 100644
--- a/jconfig.h.in
+++ b/jconfig.h.in
@@ -15,6 +15,9 @@
 /* Support arithmetic decoding when using 8-bit samples */
 #cmakedefine D_ARITH_CODING_SUPPORTED 1
 
+/* Support in-memory source/destination managers */
+#define MEM_SRCDST_SUPPORTED  1
+
 /* Use accelerated SIMD routines when using 8-bit samples */
 #cmakedefine WITH_SIMD 1